44 The Anatomy of a HORSE. Chap. 1Y. 



They are of a convex, globular Figure, inclofed within 

 their proper Lids ; which is an Orbit or Socket made for 

 ihat Purpofe out of the Bone. 



7LeE)e-lids. The Eyc-lids, of which I fliall firft take 



Notice, ferve as a Safeguard to preferve them 

 from Duft, and other external Injuries. They are com- 

 pokd of the Skin, flefhy Pannicle, and Mufcles, which are 

 a!l wrought into an exquifite Finenefs : The inner Mem- 

 brane, W'hich is very fmooth, that the Eye may move the 

 more eafily under it, is a Production of the Pericranium ; 

 the Extremities or Edges are hard and grillly, partly to 

 help their Adtion, and partly that they may meet clofe to- 

 gether. As to the Fat which lies among the Muicles, it is 

 of the fame ufe as in molt other Parts, to keep the Eye 

 moift, and eafy in its Motion. 



The Humours ami The Eye Itfelf is compofed of three 



Tanides of the Eye. Humcurs^ ^v\d (ouv Tunic/es. 

 The Adnata ^^^ ^'^ °^'^^ Tu?jiclcs is call'd Adnata ; 



it anfes from the Pericranium^ and is fpread 

 all o\'t:r the White of the Eye ; by which Means it keeps 

 it firm in its Orbit or Socket : It is of exquifite Senfe, and 

 is very full of Blood- veflels, which are perceivable at all 

 times> but efpecially when the Eye is any. ways hurt. 

 cTK o-i ■ I^^e next, which is the firft of its proper 



ro 1 a. (2!oats, is called the Sclerotica, from its 

 Hardnefs : It arifes from the Dura Mater, being opaque on 

 its hind-part, but clear and tranfparent, like Horn, on its 

 fore- part ; from whence it obtains another Name, and 

 is called the Carnea. 



The Chore' 'es '^^^ third, call'd Choroidcs, from its Re- 

 femblance to the Chorion, which inwraps 

 the Pectus in the Womb. This arifes from the Pia Mater ^ 

 as it alfo forms the innermoft Coat of the Optick Nerve. 

 It is black on its Infide, and open on its fore-part the whole 

 Breadth of \\\e Pupilla. The fore- part of this Coat is 

 alfo diftinguifhed from its back- part by the Name of Uz-ea, 

 from Its refembling the Colour of a Grape. To thi5 

 belongs the Ligamentum Ciliare, becaufe it confifts of ilen- 

 der Filaments, like the Hair of the Eye-lids. The ule of 

 thefe Filaments is to widen and conltringe the Cryftalline 

 Humour, by contrading or opening the Perforation of the 

 Uvea. 



_.. p . The innermoft or fourth Tunicle is an Ex- 



Ue Ketiaa. ^^^^^^^^ ^^ ^^^ Subftancc of the Oj>ticm^wt^ 



and 



